Aggregate notional amount specified by the derivative(s). Expressed as an absolute value.

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Derivative, Variable Interest Rate, Term

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Other Comprehensive Income (Loss), Amortization of De-Designated Hedging Instruments, after Reclassification and Tax

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Amount, after tax, of accumulated gain (loss) on derivative instrument designated and qualifying as cash flow hedge included in assessment of hedge effectiveness.

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Average fixed interest rate related to the group of interest rate derivatives.

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Average remaining period until maturity of the derivative contract, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Average variable interest rate related to the group of interest rate derivatives.

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Amount of realized and unrealized loss of derivative instruments not designated or qualifying as hedging instruments.

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Amount of decrease in the fair value of derivatives recognized in the income statement.

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Period remaining until the derivative contract matures, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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The net amount of nonoperating interest income (expense).

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The carrying amount, as of the date of the latest financial statement presented, of all assets that are pledged as collateral for the payment of the related debt obligation primarily arising from secured borrowings, repurchase agreements or other current or potential obligations, where the secured party does not have the right by contract or custom to sell or re-pledge the collateral and therefore are not reclassified and separately reported in the statement of financial position.

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The net change in the difference between the fair value and the carrying value, or in the comparative fair values, of derivative instruments, including options, swaps, futures, and forward contracts, held at each balance sheet date, that was included in earnings for the period.

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Other Assets (Derivative Instruments) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
AOCI from derivative hedging instruments:
Balance at beginning of period	$ (7,665)	$ 8,245	$ 3,121	$ (11,424)
Net (loss)/gain on Swaps	(19,706)	7,915	(30,151)	27,584
Amortization of de-designated hedging instruments, net	(743)	0	(1,084)	0
Balance at end of period	(28,114)	16,160	(28,114)	16,160
Interest Rate Contract
Derivative [Line Items]
Assets pledged	25,445		25,445		$ 32,803
Interest Rate Contract \| Agency MBS, at fair value
Derivative [Line Items]
Assets pledged	2,603		2,603		2,735
Interest Rate Contract \| Restricted cash
Derivative [Line Items]
Assets pledged	22,842		22,842		30,068
Swaps, at fair value
Derivative [Line Items]
Aggregate notional amount of derivatives	$ 2,727,000		$ 2,727,000		$ 3,217,000
Weighted average fixed-pay rate	2.42%		2.42%		2.42%
Weighted Average Variable Interest Rate	2.43%		2.43%		2.56%
Interest income/(expense) attributable to Swaps	$ 692	$ (808)	$ 1,883	$ (3,640)
Weighted average Swap rate paid	2.35%	2.05%	2.33%	2.04%
Weighted average Swap rate received	2.46%	1.92%	2.48%	1.76%
Swaps, at fair value \| Within 30 days
Derivative [Line Items]
Aggregate notional amount of derivatives	$ 0		$ 0		$ 0
Weighted average fixed-pay rate	0.00%		0.00%		0.00%
Weighted Average Variable Interest Rate	0.00%		0.00%		0.00%
Swaps, at fair value \| Over 30 days to 3 months
Derivative [Line Items]
Aggregate notional amount of derivatives	$ 0		$ 0		$ 100,000
Weighted average fixed-pay rate	0.00%		0.00%		1.71%
Weighted Average Variable Interest Rate	0.00%		0.00%		2.50%
Swaps, at fair value \| Over 3 months to 6 months
Derivative [Line Items]
Aggregate notional amount of derivatives	$ 0		$ 0		$ 100,000
Weighted average fixed-pay rate	0.00%		0.00%		1.71%
Weighted Average Variable Interest Rate	0.00%		0.00%		2.50%
Swaps, at fair value \| Over 6 months to 12 months
Derivative [Line Items]
Aggregate notional amount of derivatives	$ 200,000		$ 200,000		$ 0
Weighted average fixed-pay rate	2.05%		2.05%		0.00%
Weighted Average Variable Interest Rate	2.43%		2.43%		0.00%
Swaps, at fair value \| Over 12 months to 24 months
Derivative [Line Items]
Aggregate notional amount of derivatives	$ 1,730,000		$ 1,730,000		$ 1,630,000
Weighted average fixed-pay rate	2.30%		2.30%		2.27%
Weighted Average Variable Interest Rate	2.41%		2.41%		2.50%
Swaps, at fair value \| Over 24 months to 36 months
Derivative [Line Items]
Aggregate notional amount of derivatives	$ 500,000		$ 500,000		$ 800,000
Weighted average fixed-pay rate	2.73%		2.73%		2.57%
Weighted Average Variable Interest Rate	2.45%		2.45%		2.64%
Swaps, at fair value \| Over 48 months to 60 months
Derivative [Line Items]
Aggregate notional amount of derivatives	$ 297,000		$ 297,000		$ 417,000
Weighted average fixed-pay rate	2.88%		2.88%		2.88%
Weighted Average Variable Interest Rate	2.47%		2.47%		2.63%
Swaps, at fair value \| Over 84 months
Derivative [Line Items]
Aggregate notional amount of derivatives	$ 0		$ 0		$ 170,000
Weighted average fixed-pay rate	0.00%		0.00%		3.00%
Weighted Average Variable Interest Rate	0.00%		0.00%		2.66%
Swaps, at fair value \| Hedging
Derivative [Line Items]
Aggregate notional amount of derivatives	$ 2,700,000		$ 2,700,000
Average maturity term of swaps			22 months
Swaps, at fair value \| Minimum \| LIBOR
Derivative [Line Items]
Derivative, variable interest rate, term			1 month
Swaps, at fair value \| Maximum \| Hedging
Derivative [Line Items]
Maximum maturity term of swaps			53 months
Swaps, at fair value \| Maximum \| LIBOR
Derivative [Line Items]
Derivative, variable interest rate, term			3 months
Swap \| Non-Hedging
Derivative [Line Items]
Loss on derivative	7,400	$ 353	$ 16,300	$ 353
Realized loss	$ 6,300		$ 14,100